The invention relates generally to photovoltaic roof systems and, more particularly to, a system and method of integrating photovoltaic (PV) modules into new or existing roof structures.
Photovoltaic modules include a group of photovoltaic cells, also referred to as solar cells that are connected in series or in parallel and are encapsulated in an environmentally protective laminate. The photovoltaic cells, which are the basic building blocks of photovoltaic modules, convert solar radiation to electrical energy. Conversion of solar energy into electrical energy includes reception of light, such as sunlight, absorption of sunlight into the solar cell, generation and separation of positive and negative charges creating a voltage in the solar cell, and collection and transfer of electrical charges through a terminal coupled to the solar cell.
Photovoltaic energy is becoming a significant source of electrical power. In addition to the use of free-standing photovoltaic modules, roofs on residential and commercial building are well suited for mounting photovoltaic devices. However, it is desirable to integrate the photovoltaic device directly into the roofing structure as opposed to mounting a standard general purpose photovoltaic module on the top of an existing roof. To achieve widespread acceptance and use of photovoltaic devices on rooftops they must satisfy aesthetic requirements, and thus must integrate in appearance and configuration with the conventional roof. Moreover, they must meet all the requirements of conventional roofing materials, including ease of installation, weather tightness, fire resistance, resistance to locally anticipated weather conditions, proximate availability of materials, as well as meeting local codes and conventions. Above and beyond the requirements for conventional roofing products, photovoltaic roofing materials must provide a means for electrical connections from unit to unit, and ultimately connection into the building. For example there are a range of existing photovoltaic roof products designed to replace or augment standard roof tiles or shingles yet these photovoltaic roof tiles each have an electrical feed leading to the integrated photovoltaic cells. However, the standard roof structure does not include an electrical feed conduit for each individual photovoltaic roof tile. Thus, considerable modification is necessary to incorporate the photovoltaic roof tiles into the roof structure. Moreover, the large number of photovoltaic roof tiles or shingles (and associated electrical leads) can result in a greater likelihood of water leakage through the roof structure.
Hence, an improved technique is needed for incorporating photovoltaic modules into a roof structure.